Lactobacillus paracasei NFBC 338 producing recombinant beta-glucan positively influences the functional properties of yoghurt

The performance of a recombinant probiotic strain Lactobacillus paracasei NFBC 338, which contains the Pediococcus parvulus glycosyltransferase gene (responsible for beta-glucan production), when used as an adjunct in yoghurt manufacture was evaluated. In situ production of beta-glucan during yoghurt manufacture and storage caused a significant decrease in syneresis, confirming the water-binding ability of beta-glucan. Yoghurt textural characteristics were significantly improved due to a similar to 2-fold increase in viscosity by the end of storage (28 days at 4 degrees C). No effect on growth and viability of the yoghurt cultures (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) were found, with the recombinant probiotic strain maintaining high viability (>10(8) cfu mL(-1)) during 28 days storage. Furthermore, in situ production of beta-glucan did not influence pH, titratable acidity, or the proteolytic activity of the cultures at any storage time analysed. These results demonstrate the advantageous techno-functional properties associated with microbially produced beta-glucan in yoghurt. (C) 2011 Published by Elsevier Ltd.